"This house is secure, Olive," Horatio answered. "Spells guard it; protection surrounds it. Besides, everything that Annabelle wants is out here." Olive swallowed hard as the cat's green eyes traveled from the spectacle-shaped b.u.mp under her collar down to the sidewalk, where Leopold and Harvey were marching and lumbering along. "As long as we all stay together, we should be safe."

Olive nodded. "I want Morton to have a real Halloween," she said. "I'm not going to let the McMartins take one more thing away." She watched the glowing ghost bounce impatiently up and down on the sidewalk. A little bit of Morton's excitement seemed to flutter back to her, like a summer breeze winding through a cool autumn night. "Let's go trick-or-treating!" she said, rushing down the steps with Horatio beside her.

They wound their way up and down the street, keeping far away from the empty windows of the Nivens house. Mr. Hanniman was giving out candy necklaces. The Butlers had SweeTarts and Skittles. Mr. Fergus was distributing granola bars, but at least they were the kind with chocolate chips. All the neighbors exclaimed over Olive's creative costume, and Morton's scary costume, and the cats' adorable costumes, and then asked what Rutherford was supposed to be.

"Perhaps I should have carried my encyclopedia of the Middle Ages," Rutherford said to Olive, after explaining the significance of his blazer for the tenth time.

"When we're done, you can have all of my candy, Olive," said Morton loudly, b.u.mping Rutherford off the sidewalk.

"Well, we're not done yet," said Olive. "Don't forget about the carnival!"

"The carnival!" Morton exclaimed, running ahead, with Harvey gallumphing at his heels. "The carnival!"

Morton's antic.i.p.ation was contagious. Olive could feel it fizzing through her like bubbles in a just-opened bottle of pop, making everything seem lighter. But she couldn't get careless now, she reminded herself. It was up to her to keep an eye on everyone else. Above them, the purple sky was deepening to black. The moon, like a sliver of sharpened bone, slit the trails of pa.s.sing clouds. If a living painting was going to creep up on them, now would be its perfect chance-when the night would hide them all, and the familiar houses of Linden Street were dwindling into the distance. Olive cast a glance over her shoulder. For a moment, the rooftop of the old stone house pierced through the net of black-branched trees. Then the group turned a corner, and the last trace of the house disappeared from sight.

"We just need to stay in busy areas," said Rutherford. Olive gave a little jump, startled that Rutherford had read her thoughts so clearly. "There are witnesses all around us," he went on. "We'll be safe."

Rutherford was right. The closer they got to the junior high, the more crowded and noisy the darkening streets became. By the time they reached the last block, they were being carried along on a steady stream of kids in costumes. The cats hissed at a pack of werewolves. Rutherford was smooshed against a glittery red devil. Olive found herself sandwiched between a headless horseman and a tall gray ghoul.

She glanced up into the ghoul's tattered hood. Hidden inside was a crumbling pit where a nose should have been, lips that shriveled back from yellowing teeth, and two sagging black sockets with living eyes glimmering in their depths.

Olive looked quickly away again.

Ahead of them, the junior high was lit up like a giant brick jack-o'-lantern. Warm yellow light and bursts of music streamed from its open doors. For the first time ever, the sight of school filled Olive with a rush of comfort.

"Listen, everyone," she said softly, urging the group into a huddle just outside the front doors. "They don't usually allow pets inside, so you three cats will have to be careful not to let any grown-ups see you."

"Don't worry, Olive," Horatio murmured. "We can be discreet. At least, two of us can." He shot a look at Harvey, who was sweeping a hunchbacked bow to a girl in a Gypsy costume.

As it turned out, Olive didn't need to worry about the cats being noticed. The crowd inside the front hall was so dense, three costumed hippopotami could have gone undetected. Strands of spiderweb trailed across the ceiling. Twists of black crepe paper threaded the warm air, where the smells of popcorn and caramel mingled in a sugary fog. Olive was jostled and shoved and b.u.mped along, trying to keep her goggles firmly on her head and her feet firmly beneath her body.

"Remember to stay together!" she called over the noise.

But she was calling to no one.

4.

OLIVE STARED AROUND the teeming school hallway. Rutherford, Morton, and the cats had vanished into the crowd like five raindrops into a river.

Olive felt a sickening jolt. They had to stay together. Alone, each one of them would be vulnerable; each one could become a target. She pressed one tent-pegged hand over the lump of the spectacles. At least they were still with her. Craning around for any sign of the others, Olive let herself be carried along, through the gymnasium doors.

There, the noise and color of the hall seemed to explode outward, swelling and dimming like a burst firework. The lights hanging from the ceiling had been draped in layers of black and purple tissue, filling the room with a violet haze. The wooden floor gleamed like a mirror. Where the bleachers usually stood, rows of tents and tables flickered with false candlelight. Masked faces shifted around her. Nylon wings poked her in the sides. Robots and aliens b.u.mped past, making m.u.f.fled zapping noises with their plastic laser guns. And one tall gray ghoul loomed over her shoulder, coming just close enough to catch the corner of her eye.

Olive edged away from the ghoul's lurking figure. How come she couldn't find any of her friends, but she couldn't seem to lose one stranger?

"Rutherford?" she called, her voice useless against the carnival's roar. "Morton?"

She dodged through the crowd. If she could just find an open spot, or something tall to stand on, maybe she could get a clearer view and- "Braaaaains?" intoned a low voice in her ear.

Olive whipped around and nearly planted her nose in a platter of pinkish gray goop. The goop looked suspiciously like molded Jell-O, and the zombie holding it looked suspiciously like her science teacher, but Olive's heart gave a little shiver anyway. It gave another, harder shiver a moment later, when the zombie shuffled to one side, revealing the tall gray ghoul just a few steps away.

Was it following her?

With a burst of panic, Olive raced to the left, toward a ma.s.sive display of carved pumpkins. Safe in their glow, she paused, breathing hard, and squinted into the nearby faces.

There was no one that she recognized . . . No one but the tall gray ghoul that came gliding slowly through the crowd, its hooded face swiveling to find her.

An imaginary hand grabbed Olive by the throat. She dove behind a knot of vampires drinking blood-colored sodas. Crouching close to the floor and keeping one eye fixed over her shoulder, Olive scuttled sideways, not noticing the tall black object in her path until she had crab-walked directly into it.

The tall black object turned around.

"Well, h.e.l.lo there," said Ms. Teedlebaum, squinting down at Olive. "Happy Halloween!"

"Um . . . happy Halloween," Olive managed.

The art teacher was dressed in black from head to toe, with rows and rows of silver chains wrapped tightly around her neck. Her kinky red hair had been combed straight up, so that it jutted like a petrified ta.s.sel from the top of her head. Its tips were splattered with glossy blots of orange paint.

"I'm a paintbrush," Ms. Teedlebaum announced. "I think it's perfectly obvious, but people keep asking."

"Oh," said Olive, glancing away just long enough to see that the ghoul had sunk back into the sea of costumes. "How-how did you-"

"Get my hair to stand up like this?" Ms. Teedlebaum supplied. "That's the other thing people keep asking. I used wood glue."

"Oh," said Olive. "Will that wash out?"

Ms. Teedlebaum paused. "To be honest, I didn't think that far ahead." She shrugged, smiling again. The rows of silver chains jangled. "I guess we'll see!"

Olive nodded.

"And what about you? Are you a c.o.c.kroach?" Ms. Teedlebaum asked, gazing at Olive's goggles and scaly brown suit.

"I'm a jabberwocky. Like in Alice in Wonderland."

"Ah." Ms. Teedlebaum nodded. "I think I would prefer a c.o.c.kroach infestation to a jabberwocky infestation, wouldn't you, Alice? But I'd prefer a b.u.t.terfly infestation to either of those. Why are there never infestations of nice things, I wonder." Shaking her head thoughtfully, the red-haired paintbrush wandered away.

Olive turned in a wobbly circle, trying to bring her brain back to the present. The ghoul was still nowhere to be seen-but neither were Rutherford, Morton, or the cats. Shrieks from the Haunted Maze shot through the sugary air, making Olive twitch. She clenched her hands inside the bulky gloves.

Rutherford and the cats could find their own way home. But what if she had lost Morton for good? What if he used this chance to run away from the house, from Elsewhere, and from Olive? Or what if he came too close to those flickering jack-o'-lanterns, and the candle flames caught the edge of this costume, and- No, Olive told herself. That wasn't likely. It was much more likely that the McMartins would use this chance to separate them all, to scare and confuse them, and then to spring upon them, like wolves on a scattering herd of sheep. She had to find her friends again, before someone else did.

Olive stood on her tiptoes, searching the throng. Please, she thought. Please, please, please. And as though she had wished it into existence, a delicate greenish light, like the glimmer of a firefly, glowed through a seam in the crowd.

Olive's heart leaped.

"Excuse me," she murmured, darting past turtles and s.p.a.ce troopers and someone dressed as a dachshund in a hotdog bun. She had to keep that firefly glow in sight. "Excuse me. Excuse me."

Two giggling fairies bounced past, knocking Olive off course. "Hey!" shouted the dark-haired fairy. She squinted at Olive, her glittery green eyeliner sparkling in the dimness. "You came as a bat!"

"Ew! Don't let it get caught in your hair!" squeaked the other fairy, and the two of them fluttered away, shrieking and covering their heads.

Olive spun around, trying to find the green light again, and felt something damp brush the side of her neck. Something slick and soft and almost rotten. She halted, looking up.

The tall gray ghoul loomed above her.

Letting out a gasp that no one heard, Olive stumbled backward through the crowd. The ghoul's eyes, two glinting black pits in the shade of its hood, glided after her. She dropped to her hands and knees, veering left and then right and then left again, putting as many other bodies as she could between herself and the thing in the rotten gray robes. When she was sure she'd lost it, she bolted toward the greenish glow of Morton's costume, weaving through the crowd until suddenly she could make out the familiar shapes of Morton, Rutherford, and all three cats, gathered around the mouth of an Egyptian tomb.

Olive skidded to a halt before the tomb's cardboard walls.

"There you are!" she panted, grabbing Morton's ghostly arm. "I was so-"

"Mademoiselle!" Harvey bellowed from the corner of his mouth. "You are safe!"

"Shh!" hissed Horatio, giving Harvey a warning swat on the head.

"What did you say?" Harvey bellowed even more loudly. "The cathedral bells have made me deaf!"

"Shh!" Horatio hissed again, pressing his green nose to Harvey's splotchy one.

"I thought I wouldn't find you again," Olive gasped, gazing around at all of them. "I thought something might already have happened to you."

"We were right here the whole time," said Morton, rather grumpily. He nodded at Rutherford. "This boy has been staring at the same display forever."

"I am almost certain that these hieroglyphs are gibberish," Rutherford observed, glancing up from a painted cardboard column. "And even I-who am not an expert on ancient Egypt-know that mummy cases were placed horizontally inside of sarcophagi, not left standing up so that mummies could reach out and attack nearby people," he added as the case swung open and a bandaged arm reached out to paw at the air.

"Listen, everyone," said Olive, lowering her voice to a whisper. "I think someone is following us."

"Whom do you mean, miss?" Leopold asked, stiffening.

Horatio's green eyes sharpened. "What makes you think so?"

Olive huddled against the tomb's cardboard corner. "I should have known," she whispered to the others. "It looked too tall and too real to be a kid in a costume." She pointed into the crowd. "Do you see that tall gray ghoul, right-"

But the towering hooded head wasn't there.

It wasn't anywhere.

Olive turned back to her friends. "I don't know where it went," she said. "It was right behind me when I came into the gym. And then . . ."

The words shriveled in Olive's throat.

On the silvery wooden floor, just behind the model tomb, lay a tattered slip of gray cloth. Olive's eyes traveled upward, along the tomb's wall, and came to rest on a hand-a bony, gray-skinned, rotten hand, with its long fingers wrapped around the wall's cardboard edge.

"Run!" she screamed.

Olive streaked toward the closest exit, a pair of doors that led not to the crowded front corridor, but to one of the school's inner halls. She smacked through the doors, their heavy panels creaking open to let out the many running feet that came right behind her. Everyone shot out into the dark corridor, the cats racing protectively around Olive's ankles, Morton reaching up to grab her gloved hand.

They turned a corner into an even darker hall. Beneath their footsteps and her own gasping breath, Olive could hear the gym doors creaking open, releasing a blast of screams and laughter before whooshing shut again.

. . . Leaving one more pair of footsteps to follow them into the darkness.

5.

NO PLACE IS as silent as an empty school.

Even in the daytime, when all the lights were on and the sun was shining through the windows, Olive couldn't find her way around the junior high. Now, in the echoing darkness, she made one terrified turn after another. Her goggles slipped irritatingly over her eyes. Her heart smacked against her ribs. Panic pushed her forward like a cold, heavy hand.

"I think we need to turn the other way, Olive," said Rutherford, puffing in the blackness beside her.

"I believe he is correct, miss," Leopold added. "We ought to retrace our steps and return to the gymnasium, in order to-"

"We can't turn around," Olive argued. "That thing is right behind us! We need to find someplace to hide!"

They reached a spot where two hallways met, forming a knot of even thicker darkness. Olive halted, unsure of which way to go. Her heartbeat thundered in her ears-and still, beneath its pounding, she could hear the rustle of footsteps coming closer.

"This way. Quickly," Horatio commanded, bounding to the right.

Olive forced her legs back to a run.

They turned into another hallway, where a carpet of moonlight unrolled along the tiles beneath their feet. Olive glanced up, catching sight of the moon's bony hook gleaming through the high windows, and looked down again just in time to see Horatio dart through a gap in the hallway walls. Everyone else rushed after him.

Olive took a hasty look around. They were inside a stairwell, where a flight of steps disappeared into the darkness above. The cats crouched in the doorway, out of sight of the hall. Morton's robes flickered from the corner. Beneath the rhythm of her own heart, she could hear Rutherford's m.u.f.fled breathing. For several seconds, there was no other sound.

"I believe we lost it," Leopold murmured at last.

There was another moment of silence.

Then Morton whispered, "Who do you think it is?"

Rutherford had an instant answer. "Well, it can't be Aldous McMartin, unless Annabelle found some way to get him out of his portrait on her own, which is highly unlikely. It could be Annabelle herself, or someone in her employ who she sent after us. Or, I suppose, it might not be a costume at all."

Morton's eyes were the size of billiard b.a.l.l.s. "What do you mean? You mean that thing is a real ghost?"

"There's no such thing as ghosts," said Olive, giving Rutherford a hard look.